1. Field of the Invention
The present disclosure relates to brightness enhancement films for a liquid crystal display and manufacturing method of the same.
2. Description of Related Art
A liquid crystal display (LCD) is a popular flat panel display. An LCD includes two panels provided with field-generating electrodes, and a liquid crystal (LC) layer interposed between them. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field in the LC layer. The electric field rearranges orientations of LC molecules in the LC layer to adjust polarization of an incident light.
A liquid crystal display includes a back light unit, an optical film unit for enhancing uniformity of light luminance, and a display unit displaying images with using the uniform light.
The optical film unit includes diffusion films, prism films, and brightness enhancement films.
The brightness enhancement film includes many, e.g., hundreds thin layers. Therefore, the brightness enhancement film is thick, e.g., having a thickness of 140 to 440 μm, and the manufacturing process of the brightness enhancement film is complex.
The films of the optical film unit are respectively manufactured and disposed to have predetermined gaps between them.
The films of the optical film unit have expansion rates corresponding to temperature, and/or humidity. Thus, as the LCD size increases, the expansion discrepancies also increase, which induces an uneven film surface having waves and/or wrinkles. Uneven optical film surfaces degrade display quality.